182912domain: NAppears in sequencesNumber of -n..n arrays x(0..3) of 4 elements with zero sum and no two consecutive zero elements.at n=31A199531E.g.f.: exp( x*(1 + exp(2*x)) ).at n=7A240165Number of n X n 0..1 arrays with every element equal to 1, 2 or 4 king-move adjacent elements, with upper left element zero.at n=21A297851